Up to the present time no luminous devices have existed to indicate that a vehicle door is closed with its safety lock engaged, for which reason numerous accidents have occurred to children and adults by the unforeseen opening of a door, or by such contingencies as a crash or overturning of the vehicle when in motion, as well as thefts of articles left inside the vehicle in which the door lock was not engaged through oversight of the vehicle user.
Up to the present time, the only way to determine if the door-lock is engaged in a vehicle door has been to look at the head or upper end of the rod or button for engaging the lock, to see if it is in the upper or lower position; if by means of a lamp or luminous indication the attention of the user of the vehicle could be attracted to indicate to him that the door lock has not been set, a great number of accidents would be eliminated, as well as theft not only of articles left inside the vehicle, but of the vehicle itself as well.